Apparatus and method for drilling underwater

ABSTRACT

A system for drilling into the floor of a body of water through the employment of a drilling station located on the floor and having a torque imparting mechanism submerged therewith to transmit drilling torque to a drill string extending through the station. In deep water environments, the drill string of the system is suspended from a buoyant support station submerged within the body of water above the drilling station and an untorqued drilling fluid conduit extends upwardly from communication with the drill string to a control station proximate the surface of the body of water. The support station is lowerable to provide for lowering of the drill string as drilling takes place. The control station is buoyant and the conduit is suspended therefrom. Control devices are provided to maintain the respective stations in substantially vertically aligned interrelationship and, thus, maintain the composite length of the drill string and conduit in a relatively straight condition. A service station at the surface of the body of water is provided to selectively add length to or take length from the drilling fluid conduit and the mechanism is provided to similarly vary the distance between the support and control stations to accommodate different composite lengths of the conduit.

United States Patent [72] Inventor Arthur,I.Nelson 1998 Broadway, San Francisco, Calif.

94109 21 AppLNo. 199,494 22 Filed Jan. 7,1969 45 Patented Jul 20,1971

[54] APPARATUS AND METHOD FOR DRILLING Primary Examiner-Emest R. Purser ABSTRACT: A system for drilling into the floor of a body of water through the employment of a drilling station located on the floor and having a torque imparting mechanism submerged therewith to transmit drilling torque to a drill string extending through the station. In deep water environments, the drill string of the system is suspended from a buoyant-support station submerged within the body of water above the drilling station and an untorqued drilling fluid conduit extends upwardly from communication with the drill string to a control station proximate the surface of the body of water. The support station is lowerable to provide for lowering of the drill string as drilling takes place. The control station is buoyant and the conduit is suspended therefrom. Control devices are provided to maintain the respective stations in substantially vertically aligned interrelationship and, thus, maintain the composite length of the drill string and conduit in a relatively straight condition. A service station at "the surface of the body of water is provided to selectively add length to or take length from the drilling fluid conduit and the mechanism is provided to similarly vary the distance between the support and control stations to accommodate different composite lengths of the conduit.

[56] References Cited UNlTED STATES PATENTS' 3,491,842 1/1970 Delacouretal.. 175/6 1,331,309 2/1920 Wright 64/215 2,669,431 2/1954 Crowell 175/8X 3,101,798 8/1963 Wilsonetal... 175/8 3,310,108 3/1964 Yancey 166/.5 3,353,364 11/1967 Blandingetal. 175/6X 3,369,599 2/1968 Evans 1661.5

3 28 E] WLMA 252 42 T40 34 T A ...i

PATENIH) M20 :92: 3 59 8 ()8 sum 1 BF 5 INVENTOR fi AKTHUK J. NELSON ATTOKNEV5 PMENIEuJumwn 3, 593, 808 SHEET 3 UF 5 I NVE NTOR ARTHUR J. NELSON ATTOKNE V5 PATENTEUJULZOIQ?! 3593808 saw u 0F 5 I NVENTOR 10 ARTHUR J. N

PATENIEU JULZOIHTI 3, 593; 808 sum 5 [1F 5 INVENTOR ARTHUR J NELSON WiM Arm/mm APPARATUS AND METHOD FOR DRILLING UNDERWATER BACKGROUND OF THE INVENTION The present invention relates to the art of underwater drilling and, more particularly, is directed to the boring of wells in very deep water environments- In the prior art, various arrangements have been providedato effect deep water drilling. Certain of these employdrillingstations buoyantly supported on the surface of the body of water being worked, while othersemploy stations so located which are supported on legs extending to the floor of the body. The

latter type are, inherently, capable of working in-only relative ly shallow depths. Both typesbear'the' common characteristic that torque is imparted to the drill strings employed therewith. from a location at the surface of the body being worked. Thus, an extended length of drill string between the surface-.ofthe body and its floor is subjected to torque.

The latter characteristic has the disadvantage, as compared to conventional land drilling, that the length of drill=string under torque is increased by the depth of the body of water being worked. This disadvantage is particularly acute in very deep water. It inherently requires that the drill string be fabricated of unusually high strength and heavy material and also results. very difficult handling problems. The suspension of the weight of such a string is, in and of itself, a very major and difficult problem.

The employment of drilling stations located at the surface of a body of water also has the disadvantage that the station is subject to the hazards of surface disturbances. At sea, these hazards are particularly acute.

It is an object of the present invention to provide a deep water drilling system which avoids the disadvantages of prior art systems of the aforenoted type through the employmentof a torque imparting drilling station located at the floor of the body of waterbeing worked.

Another and more specific object of theinvention is to provide for the establishment of a submerged drilling station on the floor of a'body of water. Still another object of the invention is to provide a deep water drilling system capable of drilling to a greater depth than the systems presently in use.

Yet another object of the invention is to provide an improved and simplified drill string suspension and feedarrangement for use in deep water drilling.

Another specific object of the invention is to provide a deep water drilling system wherein the length of drill string under torque is minimized. A related object is to provide an improved torque imparting mechanism ideally suited for use in such a system.

A further object of the invention is to provide a simplified arrangement for supplying drilling fluid in a deep water drilling operation which is not dependent upon a string extending coaxially around the drill string to the surface of a body of water being worked.

The foregoing and other objects of the invention will become more apparent when viewed in light of thefollowing description and accompanying drawings.

SUMMARY OF THE INVENTION The present invention may be summarized as a method and apparatus for effecting deep water drilling through the employment of a drilling station located at the floor of a body of water being worked. In its more specific aspects, the invention is concerned with an improved drill string suspension arrangement employing buoyant means submerged within the bodyof water being worked to support the weight of the string and maintain it under tension over substantially its entire length. It is also concerned with an arrangement wherein lowering of the drill string during drilling may be effected by simply further submerging the buoyant support means, rather than continuously adding length to the drill string.

The foregoingabstract summarizes the elements employed in the'apparatus and'method of the invention. A more precise definition of the invention is found in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view diagrammatically illustrating the entiresystem of the invention in the condition it would assume during a drilling operation, with parts thereof broken away for, purposes of compactness.

FIG. 2 is a, partial elevational view diagrammatically illustrating the drilling station with the base and superstructure portions thereof separated as they might be during a servicing operation.

FIG. 3 is a sectional elevationalview of the drilling station in an assembled condition, with partsthereofbroken away.

FIG. 4. is a cross-sectional view (of the torque tube and drill string of the invention.

FIG. 5 is asectionalview taken on the plane designated by lines 5'-5 of FIG. 4.

line cables connecting the respective stations employed in the system.

FIG. 9 is a sectional view taken on the plane designated by lines 9-9-of FIG. 7 illustrating one of the elements of the tension equalizers shown in FIG. 8.

FIG. '10 is a sectional view, in elevation with parts thereof broken away, showing the construction of the joint between the drill string and the drilling fluid supply line and the support arrangement for the drill string on the support station.

FIG. 11 is an elevational view diagrammatically illustrating the support station in a condition out of vertical alignment with the stations to either side thereof.

FIG. 12 is a plan view diagrammatically and schematically illustrating the vertical and rotational alignment structure of the invention.

FIG. 13 is a partial elevational view with parts thereof shown in section, illustrating the movably interrelated elements at one side of the vertical and! rotational alignment structure.

FIG. 14 is a sectional view taken on the plane designated by lines 14-14 of FIG. 3 illustrating the shuttle type sealing mechanism employed to establish a fluidtight connection between the drill string and the casing of a hole being drilled thereby.

FIG. 15 is a sectional view taken on the plane designated by lines 15-l5 of FIG. 14.

FIG. 16 is an elevational view, in section, diagrammatically illustrating the sequential operation of the portion of the shuttle type sealing mechanism shown in FIG. 4 which cooperates with enlarged torque collars on the drill string. The portions of this drawing identified as A, B and C represent three sequential stages of the same structure.

7 FIG. 17 is a sectional view of a coupling which may be employed when the intermediate support station is omitted from the system.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The Upper Structure Referring now to the overall arrangement of the system illustrated in FIG. l,.a service station in the form of a barge is designated therein in its entirety by the numeral 20. The basic arrangement of this station is similar to the hull shown in my previous Pat. No. 2,933,837. Specifically, the hull of the station is formed with an open alleyway through which a conduit carrying boom 22 may swing in a generally vertical plane. This boom is secured to the hull of the station for pivotal movement about a transverse horizontal axis 24. Although not illustrated, it should be understood that the hull is provided with work surfaces to either side of the alleyway and that the hull would be suitably compartmented to provide work, storage, and living accommodation areas. It is also anticipated that the hull of the station 20 would be of submarinelike character and selectably submergible to any desired degree.

A derrick 26 is mounted on one end of the station 20 to provide for the lowering of sections of pipe and other equipment into the body of water on which the station is supported. In FIG. 1, the body of water is designated by the numeral 28. The station 20 is also provided with propulsion devices to effect its movement in any desired direction. As illustrated, these devices take the form of water discharge jets 30 and 32 mounted on the ends and sides, respectively, of the hull beneath its normal water line. While not illustrated, it should be understood that a plurality of these jets corresponding to the jets 32 would be provided on both sides of the hull. Thus, through select operation of the jets, any desired traversal of the station 20 may be effected.

A control station 34 is secured to the distal end of the boom 22 and to one end of the service station 20 for vertical translation relative to the service station. It comprises, as its basic element, a frameworklike superstructure 36 of a pyramidical shape. The apex of this structure is secured to the distal end of the boom 22 by flex joint 38 (e.g., a balljoint) and the corners of the framework are secured to pontoons 40 which provide buoyant support therefor. A tubular support 42 is fixed to the superstructure and depends downwardly therefrom in alignrnent with its apex. This structure, as will become more apparent subsequently, supports the alignment control structure for the control station and provides for the extension of conduit through the station. A guide 44 is fixed to and depends downwardly from the under surface of the station 20 for guiding engagement with mating guide structure (not illustrated) on the control station 34. Through the latter arrangement, movement of the control station relative to the service station is confined to a generally vertical path. The solid and phantom line representations of the control station 34 illustrate the approximate extremes of its upper and lower movement respectively.

The Drilling Fluid Supply Conduit The Support Station The first structure below the fitting 50 comprises a buoyant support station 52. This station is of open bottomed domeshaped configuration and similar in construction and mode of operation to that disclosed in my Pat. No. 3,359,741. It is designed to confine a volume of gas (e.g., air) above the open bottom thereof for buoyant support purposes. Gas is supplied to the station through a conduit 54 and valve mechanism 56.

The conduit 54 leads to a suitable source of pressure (not il- 7 lustrated) on the service station 20. It is anticipated that the gas supply arrangement may correspond to that of my afore mentioned Pat. No. 3,359,741.

The valve mechanism 56, as can be seen from FIG. 7, is designed to maintain a predetermined volume of gas within the station 52 and to provide means to selectively vary this volume. It comprises: a float valve 58; a flexible conduit 60 connecting the conduit 54 to the valve 58; a screw and a guide 62 and 64, respectively, supporting the float valve 58 for select vertical movement in the gas chamber of the station 52; and, an electric motor 66 coupled to the upper end of the screw 62 to effect its selective turning and resultant vertical movement of the valve 58. The valve 58 functions to admit gas into the chamber of the station 52 whenever the water level within the chamber rises above the level of the valve. Through raising and lowering of the valve 58 by activation of the motor 66, the water level within the chamber may be selectively varied. While not illustrated, it should be understood that the electrical control lines for the motor 66 would lead to suitable manual and/or condition responsive control means on the service station 20. The motor 66, as well as the other submerged motors in the present system, would preferably be of the type disclosed in my copending application Ser. No. 570,197, filed Aug. 4, 1966 now Pat. 3,432,704 issued Mar. 11,1969.

Reference is now made to the detailed construction of the fitting 50, as viewed in FIG. 10. This fitting comprises, as its basic components, the following elements: a tubular housing 68 fixed to the upper chamber forming wall, designated 70, of

the station 52; a first tubular conduit element 72 coupled to the lower end of the conduit 46 by a coupling 74 and extending downwardly therefrom slidably into the housing 68 for rectilinear movement relative thereto; and, a second tubular conduit element 76 received within the housing 68 and around the conduit element 72 for rotational movement relative thereto. The housing 68 has roller guide arms 78 fixed to and extending upwardly therefrom for guiding engagement with the conduit element 72. It is also provided with an involute flushing chamber 80 extending around the element 72 and opening into the element 76. This chamber provides for the supply of flushing fluid to the area between the elements 72 and 76 and is closed at its upper end by an annular seal 82 interposed between the housing 68 and the exterior surface of the element 72. Flushing water is supplied to the chamber 80 by conduit 84 leading to a pump 86 (see FIG. 7) and/or any suitable supply of water. The conduit element 76 is supported in concentric alignment with the element 72 for rotation relative thereto and relative to the housing 68 by annular bearings 88 and 90. A seal 92 is supported by the housing 68 in juxtaposition to the bearing 88 to prevent fluid from escaping past the hearing. The lower end of the conduit element 76 has a thrust collar 94 fixed thereto for rotation therewith. This collar is supported on a thrust surface 96 fixed to members 98 which span the lower end of the station 52. The members 98 are fixed against movement relative to the station 52 and, thus, the thrust surface 96 functions to support the conduit element 76 against rectilinear movement relative to the station.

The Upper Guy Lines Guy lines 100, I02 and 104 extend between the control station 34 and the support station 52. The upper ends of these lines are secured to the tubular support 42 (see FIG. 8) through means of a tension equalizing device 106 corresponding to that of my Pat. No. 3,359,741. This device, as is developed in detail in my prior patent, comprises two beams I08 and 110 pivoted to the tubular support 42 and a third beam 112 suspended from the distal ends of the first two beams by intermediate cables 114 and 116. The guy lines and 102 are secured, respectively, to the close ends of the beams 108 and 110, and the guy line 104 is secured to the center of the beam 112. The pivot axes of the beams 1108 and are spaced from the distal and close ends thereof in a 2-to- 1 ratio. Through the geometric interrelationship of the beams and the pivot and cable connections thereof, tension in the guide lines 100, I02 and I04 is equalized.

The lower ends of the guy lines 100, 102 and 104 are secured, respectively, to reels mounted within the station 52. Two of these reels, designated 118 and 120, are illustrated in FIG. 7. While the third reel is not shown, it should be understood that it corresponds to those illustrated. The reels correspond identically in construction and, accordingly, the parts thereof are designated by like numerals. Each reel comprises: a pair of vertically spaced supportsl22 and 124 fixed to the housing 68; a vertically disposed shaft 126 journaled between the supports and having a drum 128 fixedly mounted thereon; a guide sheave 130 mounted for movement across the drum responsive to the turning thereof to direct line thereonto; and, drive pinions 132 keyed to the shaft 126 to effect turning thereof. The pinions 132 are simultaneously driven by a bull gear 134 joumaled therebetween. The hull gear is supported by a journal (not illustrated) mounted on the station 52 and driven by an electric motor (also not illustrated). The guy lines extend into reeved engagement with the respective drums 128 through tubes 136 sealingly secured to and opening through the upper wall 70 of the station 52. The tubes are provided so that gas contained in the upper portion of the station will not escape through the openings in the wall 70 provided for passage of the guy lines.

The guy lines 100, 102 and 104 provide means whereby any I desired portion of the load from the station 52 may be transmitted to the control station 34. This function is particularly important during the installation process when the various components of the system are being lowered into a body of water. During actual drilling, the guy lines function to pull the control station down with the station 52. The reels within the station 52 provide for selective varying of the length between the respective stations. This is necessary during installation and removal of the system and is also periodically necessary during the drilling operation. Specifically, during drilling it is necessary to periodically lengthen the guy lines to permit the station 34 to be elevated and to facilitate the addition of additional lengths of conduit to the drilling fluid conduit 46.

The support station 52 carries a tubular support 138 similar in structure and function to the support 42 of the station 34. The support 138 is mounted on the station 52 in concentric alignment with the housing 68 through means of a drumlike member 140 sealingly secured to and depending downwardly from the wall 70 of the station and an annular wall 142 secured between the member 140 and the support. While not illustrated, it is also anticipated that the member 140 would be reinforced by spokelike webs extending between its outer surface and the inner surface of the wall 70. The support members 98 (see FIG. for the thrust surfaces 96 span the station 52 through the member 140.

The Drill String and Drilling Station Referring now again to FIG. 10, there it can be seen that the tubular conduit element 76 terminates in a nipplelike portion 144. This portion is fixedly secured to a drill string 146 through-means of a coupling 148 of generally rectangular exterior cross section. The drill string 146 is suspended from the station 52 through means of the thrust collar 94 and extends to and through a drilling station 150 located on the floor, designated 152 of the body of water 28.

The drilling station 150, as can be best seen from FIG. 2, comprises a base portion 154 and a removable superstructure portion 156. These portions couple together to form the composite structure seen in FIGS. 1 and 3. The base portion comprises a pontoon similar to that of the support station 52 of dome-shaped open bottomed construction. The outer wall of this pontoon is designated by the numeral 158 and has an annular flange 160 fixed thereto and extending therearound and against which a similar flange 162 on the superstructure por- ,;tion 156 is adapted to. seat. Solenoid operated latches 164 are mounted on the superstructure portion 156 for engagement with the flange 160 when the flanges 160 and .162 seat. These latches may. be of anydesired construction and are solenoid operated so that they may be remotely actuated topermit the base and superstructure portions tobe remotely released. The superstructure po'rtion,156, as can be best seen from FIG. 3,

comprises a framework 166 of generally .pyramidical shape terminating in ajoumal 168 at its apex. The journal rotatably support a torque tube 170 extending longitudinally of 'the framework 166. The lower end of the torque tube 170 is rotatably received in a journal 172 secured against longitudinal movement relative thereto. The joumalhas an annular bearing member 174 of frustoconical peripheral configuration fixed thereto. Theexterior surface of the latter member is adapted, upon nesting of the base and] superstructure portions, to seat in a conieal flange 176 fixed to and extending upwardly from the wall 158 of the base portion. 1

The pontoon of the base portion 152 is provided with a valve mechanism 56a corresponding substantially to the mechanism 56 of the station 52. For the sake of concise reference, the elements of the mecha'nism56a corresponding to those of the mechanism 56 are designated by like numerals followed by the subscript a," as follows: float valve 580; flexible conduit 60a; screw 62a; guide 64a; and, motor 660. The flexible conduit 60a is connected to a supply conduit 54a, corresponding substantially to the conduit 54, mounted on the framework 166. To permit the conduits 54a and 60a to separate upon removal of the superstructure portion 156 from the base portion 154, a disengageable coupling 178 is provided between the conduits. The end of the conduit 54a extending into this coupling is provided with a check valve (not illustrated) which is cooperable with the coupling to prevent the flow of fluid through the conduit 54a when it is removed from the coupling. The motor 66a is also mounted onwthe framework 166. To permit its separation from the screw 62a upon separation of the base and superstructure portions, a releasable coupling 180 is interposed between the drive shaft of the motor and the screw.

From the foregoing description, it can be seen that the buoyancy of the drilling station 152 :may be controlled in a manner corresponding to that of the support station 52. While not illustrated, it should be understood that suitable supply and exhaust lines would be provided for this purpose. Reference is made to my Pat. No. 3,359,741 for a conduit system suitable for this purpose.

The Drilling Station Legs The base portion 154 is provided with three individually extensible and retractable telescopic legs 182. Each of these legs, as can be seen from FIG. 3, comprises: an upper tubular section 184 fixed to the outer wall 158; a lower tubular section 186 telescopically received within the upper section for extension and retraction relative thereto; an axially extending screw 188 rotatably received within the section 184 and locked against axial movement relative thereto by a bearing 190 a out 192 threadably received on the screw 188 and fixed to the section 186 so that turning of the screw effects axial movement of the section 186; a guide 194 rotatably received on the lower end of the screw 188 and slidably received within the section 186; and, a separable coupling 196 having one portion fixed to the upper end of the screw 18 and the second portion removable therefrom mounted on the superstructure portion 156 for removal therewith. The legs 182 are arranged in a generally pyramidical pattern to provide a tripodlike support. Since they correspond identically in construction, each is designated by the same reference numeral. The upper tubular section 184 of each of the legs is reinforced by braces 198 (see FIGSJ and 2) fixed between the lower end thereof and the wall-158 of the base portion 154. While not illustrated in detail ,-it should be understood that the lower sections of each of the legs terminate in a foot portion suitable for engagement with the floor of a body of water within which the drilling station 150 is disposed. I

The composite weight of the drilling station 150 is supported through the provision of both the buoyant tank within the base portion 154 and the floor engaging legs 182. A certain amount of the weight is also supported by guy lines (as will be developed subsequently) to the station. The amount of supportthus provided is dependent on the tension in the lines. The legs provide for secure engagement of the station with the floor and, thus, enable torque to be imparted to the drill string 146 from the drilling station. The amount of load supported on the legs may be selectively varied by varying the buoyancy of the base portion 154. The latter characteristic facilitates the positioning of the base station on a surface which might not otherwise be capable of stably supporting the drilling station.

As noted in the foregoing discussion, the legs 182 are individually adjustable. This feature ,is provided to facilitate leveling of the base station 150 on the floor of a body of water of uneven terrain. Drive for each of the legs 182 is provided by three individual electric motors 200 (only one of which is illustrated) mounted on the superstructure portion 156 in a generally vertically disposed position. These motors perform, alternatively, the function of individually driving the legs 182 or compositely driving a rotary table 202 fixed to the torque tube 170. To facilitate the latter operation, the motors 200 are positioned at substantially equal annularly spaced positions around the table 202. The table 202 is of annular configuration and formed with gear teeth at its outer periphery mating with drive pinions 204 (see FIGS. 3 and 6) mounted on the drive shafts 206 of the motors. F IG. 6 shows that each of the pinions 204 is rotatably received on the shaft 206 therefor for select keying thereto through a clutch mechanism 208. Each shaft 206 also rotatably receives a bevel pinion 210 for select keying thereto through the clutch mechanism. It is through the latter pinion that driving torque is imparted to the screws for the legs 182.

Each of the clutch mechanisms 208 comprises: a key 212 fixed to and extending longitudinally of the shaft 206 therefor; a drive sleeve 214 slidably'received around the shaft 206 in keyed engagement with the key 212 for movement between the pinions 204 and 210; first andsecond drive dogs 216 and 218, respectively, secured to and extending from the surfaces of the sleeve 214 in opposition, respectively, to the pinions 204 and 210; first and second drive sockets 220 and 222 formed, respectively, in the pinions 204 and 210 for driving engagement by the dogs 216 and 218, respectively, upon movement of the sleeve 214 to a position engaging, alternatively, the dogs therewith; a ball bearing 224 having an inner race secured to the outer periphery of the sleeve 214 and an outer race rotatable relative thereto; an actuating lever 226 pivotally supported on a pedestal 228 intermediate its ends and having one end secured to the outer race of the bearing 224 to impart rectilinear movement thereto and resultant movement to the sleeve 214; a solenoid 230 having an actuating rod 232 secured to the lever 226 to selectively move it in an upward direction and thus move the sleeve 214 downwardly and into engagement with the pinion 210; and, a compression coil spring 234 interposed between the solenoid 230 and the lever 226 to normally urge the lever in a downward position wherein the sleeve 216 is drivingly engaged with the pinion 204. The pedestal 228 and solenoid 230 are mounted on a plate 236 fixed to the end of the motor 200.

Through the foregoing arrangement, the spring 234 normally maintains the clutch mechanism 208 in a condition wherein the pinion 204 is driven by the motor and, thus, functions to drive the rotary table 202. Upon select activation of the solenoid 230 to retract the rod 232, the sleeve 214 is moved out of driving engagement with the pinion 204 and into driving engagement with the pinion 210. The latter operation, as will become more apparent subsequently, functions to drive the legs 182 operatively associated with the motor 200. It should be understood that the pinions 204 and 210 are rotatably received on the shaft 206 and secured against rectilinear movement relative thereto. The latter function may be accomplished by any suitable means, such as snap rings on the shaft 206.

In addition to the aforedescribed structure, the balance of the drive structure for each of the legs 182 comprises: a shaft 238 journaled between supports 240 mounted on the base portion 154; a first bevel pinion 242 fixed to one end of the shaft 238 in mating engagement with the bevel pinion 210; a second bevel pinion 244 fixed to the outer end of the shaft 238; and, a third bevel pinion 246 fixed to a shaft extending from the portion of the coupling 196 mounted on the base portion 154. This arrangement imparts turning movement from the motor 200 to the screw 188 when the solenoid 230 associated with the motor is activated.

The legs 182 are controlled to maintain the drillingstation 150 in a level condition through means of a levelling control 248 (see FIG. 3). This control comprises: a closedtoroidal reservoir 250 fixedly supported on the superstructure portion 156; a volume of oil 252 contained within the reservoir to a level of about one-half the total reservoir depth; three floats 254 (only one of which is illustrated) buoyantly supported on the oil within the reservoir for guided movement in independent vertical planes; and, a pair of switch contacts, only one of which pairs is illustrated, disposed in opposition to each of the floats 254 for alternate contact thereby. Each pair of contacts comprises an upper contact 256 and a lower contact 258. Each of the floats is designed to control one of the legs 182 and is disposed in the same radially extending vertical plane as the leg which it controls. For example, as seen in FIG. 3, the illustrated float 254 lies in the same radially extending plane as the illustrated leg 182 and controls operation of this leg.

In operation, whenever the float 254 aligned with oneof the legs 182 engages one of the contacts to either side thereof, the motor 200 and solenoid 230 for this leg is energized. Engagement of the lower contact 258 functions to energize the motor 200 in a direction retracting the leg 182 associated therewith, while engagement of the upper contact 256 functions to ener-' gize the motor 200 to extend the leg associated therewith. During actual operation, it is likely that all three of the legs will be simultaneously activated to lengthen the legs or leg to one side of the drilling station while shortening the leg or legs to the other side of the station. Once the station is level, the floats 254 assume a neutral position out of engagement with the contacts to either side thereof and the solenoids are deactivated to permit the motor 200 to drive the table 202. The latter function is effected through the normal operation of the springs 234 associated with the drive pinions for each of the motors 200.

The Lower Guy Lines The stations 52 and 150 are connected by guy lines a, 102a and 104a corresponding substantially to the aforedescribed guy lines 100, 102 and 104, respectively. The guy line 104a is not illustrated in the drawings. At their upper ends, the guy lines 100a, 102a and 104a are connected to a tension equalizing device 106a corresponding to the device 106, with the exception that it is mounted on the tubular support 138, rather than the support 42. The lower ends of the guy lines 100a, 102a and 104a are secured to the superstructure portion 156 through means of reels 118a mounted thereon and corresponding substantially to the aforedescribed reel 118. The components of the reels 118a corresponding to the reel 118 are designated by like numerals followed by the subscript a" as follows: supports 122a and 1240; shaft 126a; drum 128a; guide sheath 130a; pinion 132a; and, bull gear 134a. The bull gear 134a is of annular configuration and journaled on the superstructure portion 156 in concentric alignment with the torque tube by a bearing (not illustrated) mounted on the superstructure portion. lt functions to simultaneously drive the reels 118a for all of the guide lines 100a 102a and 104a to effect the lengthening or shortening thereof.

Drive for the bull gear 1340 is provided by power takeoff shaft 262 adapted to couple it in driven engagement with the peripheral gear on the rotary table 202. The upper end of the shaft 262 has a drive pinion 264 fixed thereto in mating engagement with the bull gear 134a. The lower end of the shaft 262 carries adriven pinion 266 received thereon for rotation relative thereto and mated engagement with the gear on the periphery of the rotary table 202. The shaft 262 is journaled between bearings 268 and 270 mounted on the superstructure portion 156. To selectively energize the shaft 262 and, thus, drive the bull gear 134a and the associated reels, a clutch mechanism 208a is provided for the driven pinion 266. This mechanism corresponds identically to the mechanism 208 with the exceptionthat it controls only the single pinion 266 and normally functions to maintain this pinion in an idling condition. Upon energization of the solenoid in the mechanism 208a, it functions to lock the driven pinion to the shaft 262. This, in turn, effects driving of the shaft responsive to turning movement of the table 202.

To maintain a uniform tension on the guy lines 100a, 102a and 1040 upon movement of the station 52 towards the station 150 during drilling, weighted sheaves 272 (only one of which is illustrated) are suspended thereon as seen in FIG. 3. These sheaves are free to move vertically as the upper ends of the guy lines move and are guided in a vertical path by a suitable guide structure (not illustrated). At least one of the sheaves 272 cooperates with limit switches (not illustrated) disposed at the extremes of its movement to effect control of the clutch mechanism 208a. The lower of these switches functions to engage the clutch and thus energize the reels 118a whenever the weighted sheaves lower to a maximum degree. The upper of these switches functions to deactivate the clutch mechanism 108a upon raising of the weighted sheaves to a maximum degree. Thus, tension in the guy lines 100a, 102a and 104a is continuously maintained.

The operation of the reels 118a may be monitored to sense the rate at which the station 52 is being lowered towards the station 150. This rate, as will become more apparent sub sequently, corresponds to the drilling rate of the system. This monitoring may be effected by a suitable monitoring mechanism coupled to the support shaft of one of the reels. Such a mechanism is represented in FIG. 3 by a box 274. Any suitable relay system may be employed to transmit the signals of this mechanism to the service station 20.

The Torque Tube And Drill String Construction The detailed construction of the torque tube 170 can best be seen from FIGS. 3, 4 and 5. As noted in the foregoing discussion, the torque tube is joumaled for rotation by bearings 168 and 172 at its upper and lower ends, respectively. In addition to these bearings, an interrriediate bearing 276 also supports the tube on the framework 166 of the superstructure portion 156. While the bearings are provided primarilyjfor lateral support, at least one of them also acts as a thrust bearing. The thrust function of the bearing or bearings is simplyprovided to locate the tube axially, since no appreciable thrust is imparted thereto during drilling. The bearings 168 and 276 function to maintain the tube in axial alignment with the superstructure portion 156 when it is removed from the base portion 154 and at least one of these I must act as a thrust bearing to prevent the tube from separating from the superstructure portion when the portions are separated.

The interior of the torque tube 170 has a pair of oppositely disposed longitudinally extending keys 278 fixed thereto and extendingover its full length. These keys are provided to slidably mate with longitudinally extending keyslots 280 formed inopposite sides of the drill string couplings 148. Through this arrangement, torque imparted to the torque tube 170 through means of the rotary table 202 fixed thereto is transmitted to the drill string 146. The couplings 148 are spaced apart by a distance less than the length of the keys 278 within the torque tube 170. Thus, at least one coupling is at all times keyed to the torque tube. The slots 280 are flared out at their end portions to facilitate their alignment with the keys 278. It should be noted, however, that there is no substantial tendency for a coupling entering the upper end of the torque tube to beam of alignment with the keys 278. This results because the keyways in the couplings are initially set in longitudinal alignment and there is no substantial twisting torque betweena coupling received within the torque tube 170 and a coupling disposed thereabove. The absence of any such twisting torque results because the length of the drill string 146 above the torque tube is free to rotate and is subjected to substantially no turning resistance. Naturally, the length of the drill string beneath the torque tube 170 is subjected to twisting torque as a result of the drilling operation. From FIG. 1, it can be seen that the lower end of the drill string 146 terminates in a rotary drill bit 284. This bit is relatively conventional in that it is designed to drill a hole of a diameter greater than that of the drill string.

Referring now in detail to FIG. 5, there it can be seen that the couplings 148 each comprise a tubular body section formed with internal screw threads 286. These threads are generally of the tight fitting type. They are designed to mate with external threads 288 formed on the ends of the drill string pipe lengths to be joined thereby.

In the preferred embodiment illustrated, the coupling is threaded halfway on to the end of one of the drill string pipe lengths and then welded into place so as to be locked thereto. In the drawings, such a weld is designated by the numeral 290. An annular gasket 292 is then inserted into the coupling and then the end of the other drill string pipe length is threaded thereinto so as to abut against the end of the welded pipe length and squeeze the gasket between the abutting ends. To

accommodate the gasket, the ends of the pipe lengths are preferably externally bevelled. Once the ends of the pipe lengths are screwed into abutting engagement, a set screw is screwed through the wall of the coupling and into engagement with the nonwelded length to prevent it from screwing out of the coupling. Ideally, the threads on the coupling and pipe lengths are such that during normal drilling drilling torque tends to screw the lengths more tightly against each other within the coupling. The set screw is provided primarily to prevent the pipe length engaged thereby from unscrewing from the coupling when the drill string is being turned out.

The Support Station Alignment Mechanism In order to maintain vertical and rotational alignment between the support station 52 and the drilling station 150, an alignment mechanism 296 is mounted on the underside of the station 52 for cooperation with the guy lines a, 102a and 104a. The control portion of this mechanism comprises: three rods 298 fixed to and depending downwardly from the wall 142 at equal angularly spaced positions around the drill string 146; a fourth rod 300 fixed to and depending downwardly from the wall 142 at a location between a pair of the rods 298;

'a plurality of eye bolts 302, one of which is pivotally supported on each of the rods 298 and extends inwardly therefrom; a magnetic vane 304 on each of the bolts .302; an arm'306 fixed to and extending inwardly from the bolt 300; a magnetic vane 308 at the inner distal end of the arm 306; a ring 310 suspended from the guy lines 100a, 102a and 1044 and having first slot 312 therein slidably receiving the bolts 302 and a second slot 314 therein slidably receiving-the arm 306; a plurality of first magnetic vane switches 316, one of which is mounted on the ring 310 adjacent each of the slots 312 for activation by the vane on the bolt extending therethrough; a second vane switch 318 mounted on the ring 310 adjacent the slot 314 for activation by the vane 308 of the arm 306; a first electrical lead 320-extending from a source'of current and connected to one side of each of the switches 316 and 318; a second electrical lead 322; and, an electric motor 324 connected across the leads 320 and 322.

The motion imparting portion of the alignment mechanism 296 comprises: a water manifold 326 (see FIGS. 7 and 12) of annular configuration fixedly supported on the station 52 in concentric alignment therewith; a centrifugal pump 328 interposed in the manifold 326 to effect the pressurization thereof, said pump being driven by motor 324; a plurality of radially extending nozzles 330, one of which is secured in fluid communication with the manifold 326 in radialalignment with each of the bolts 298; an electrically operated valve 332 for each of the nozzles 330 to normally maintain it in a closed condition and, upon energization, effect its opening; a pair of electrical leads 334 and 336 connecting each of the valves 332 across the switch associated with the bolt 298 radially aligned with the nozzle thereof and the lead 322; an annularly extending nozzle 338 secured in fluid communication with the manifold 326; an electrically operated valve 340 interposed in the nozzle 338 to normally maintain it in a closed condition; and, a pair of electrical leads connecting the valve 340 across the switch 318 and the lead 322. 7

Through the foregoing arrangement, when the station 52 traverses laterally relative to the station 150, the radially extending nozzles 330 are selectively activated to return these stations to a vertically aligned condition. For example, when the station 52 moves to the right, as illustrated in FIG. 11 and by the phantom line representation in FIG. 12, the nozzle 330 at the right of the manifold 326 is opened to permit water to be jetted therefrom and thus react to propel the station 52 back to the left. It should be appreciated that more than one of the nozzles might be simultaneously activated, depending upon the direction in which the station 52 moves out of vertical alignment with the station 150. It ismovement of the ring 210 relative to the station 52 and responsive closing of the main switches 316 which effects selective operation of the nozzles. The phantom line representation in FIG. 13 clearly shows this movement. It results because the ring 310 is supported on the guy lines 1000, 102a and 1040.

It is here noted that vertical misalignment of the station 52 relative to the station 150 may result from any number of causes. For example, ocean currents or movement of the station may impart lateral misaligning forces to the station 52. Rotational misalignment, however, is likely to occur primarily as the result of turning of the drill string 146 within the station 52. Thus, if the string turns in a clockwise direction, as viewed in FIG. 12, this will be the primary direction of rotational misalignment. For this reason, the nozzle 338 is positioned to react only in a direction moving the station 52 in a counterclockwise direction. lts operation is controlled by the switch 318. This switch is activated whenever the station 52 moves in a clockwise direction relative to the ring 310 sufficient to close the main switch 318.

If there is need to provide reaction force to turn the station 52 in either direction of rotation for alignment purposes, a pair of nozzles 338 facing in opposite directions may be provided. In this case, it is simply necessary to position a vane switch 318 to either side of the vane 308 on the arm 306 and to wire the oppositely directed nozzles to the respective switches. Thus, the vane 308 would function, alternatively, to open either of the nozzles to effect rotational movement of the station 52 in either a clockwise or counterclockwise direction to reestablish rotational alignment.

While the pump 328 has been described as being continuously driven by the motor 324, it should be understood that the motor may be wired so as to be activated only upon closing of one of the switches 316 or 318. It should also be understood that the pump 328 would normally be supplied with water directly from the body of water within which the station 52 is submerged. Where desired, however an external source might be employed.

The Control Station Alignment Mechanism The control station 34 is maintained in vertical and rotational alignment with the support station 52 through means of an alignment mechanism 2960. This mechanism corresponds substantially to the mechanism 296, with the following exceptions:

1. the rods of the mechanism (those corresponding to the rods 298 and 300) are fixed to and depend from a structure 346 fixed to the support 42;

2. the ring (i.e. that corresponding to the ring 310) is suspended on the guy lines 100, 102 and 104; and,

3. the vane switches function to control operation of the jets 30 and 32, rather than a manifold and nozzle arrangement. The mechanism 296a includes no structure corresponding-to the manifold 326 and the nozzles 330 and 338. It, rather, functions to control the propelling function of the jets 30 and 32. This, in turn, controls the position of the station 34, since the guide 44 maintains the stations 20 and 34 in vertical and rotational alignment.

The Drilling Fluid Diverter and Return Conduit In the operative condition illustrated in FIG. 1, drilling fluid return (i.e. "mud return) from the annulus around the drill string formed by the bit 284 is provided by a diverter assembly 348. This assembly is sealingly mounted on the upper end of a casing cemented into the hole being drilled. It comprises separable bottom and top sections 352 and 354, respectively, of tubular configuration. The opposed ends of these sections are flanged for mating sealed engagement and removably coupled together by jaws 356 mounted on the section 354 for select gripping engagement with the flange on the section 352. While not illustrated, it should be understood that the jaws are remotely operable through means of suitable actuators, such as solenoids. These are generally controlled from the service station 20 so that the top section may be removed from the bottom section when desired.

The bottom section 352 has a branch conduit 358 coupled in sealed fluid communication with the interior thereof by joint 360. Preferably, the joint 360 is of the ball joint type to provide for flexibility between the conduit 358 and the section 352. The branch conduit 358 is coupled in fluid communication with a return drilling fluid conduit 362 by a ball joint 364. From the ball joint 364, the conduit 362 extends upwardly to a reprocessing system on the station 20. The conduit 362 is suspended through means of a support system of the type disclosed in my Pat. No. 3,359,741. In FIGS. 1 and 2, the pontoons of this system are diagrammatically represented and designated by the numeral 366.

The top section 354 of the diverter assembly is illustrated in detail in FIGS. l4, l5 and 16. The purpose of this section, as will become more apparent subsequently, is to establish a fluid tight seal between the assembly and the outer periphery of the drill string 146 while, at the same time, permitting the couplings 148 to pass through the assembly. To achieve this purpose, it incorporates a fixed housing structure having a drill string engageable shuttle mechanism mounted therein for translation relative thereto. The housing structure comprises: a first cylindrical element 368 fixed to and extending upwardly from the flange at the lower end of the bottom section 352; an annular flange 370 welded to and extending around the upper extremity of the element 368; an annular cap 372 fixedly secured over the flange 370 by a snap ring 374; a second cylindrical element 376 fixed to the cap 372 and extending upwardly therefrom to the bearing member 174; an annular flange 378 welded to and extending around the upper end of the element 376 in fixed engagement with the underside of the bearing member 174; an annular seal 380 fixedly supported on and extending upwardly from the cap 272; a stop post 382 fixed to and extending upwardly from the cap 372; and, a spring guide rod 384 mounted between the cap 372 and the underside of the bearing member 174. The bearing member 174 is fixedly secured to the flange 378 through means of an annular collar 386 welded to the underside of the member and a snap ring 388 lockingly interposed between the collar and the flange. The shuttle mechanism within the top section comprises: a tubular cylinder 392 concentrically received within the first and second cylindrical elements 368 and 376 in peripherally sealed engagement with the seal 380 for rectilinear and rotational movement relative thereto; an annular flange 394 fixed to and extending around the upper end of the cylinder 392; an annular disc 396 received around the cylinder 392 beneath the flange 394 and having the rod 384 extending therethrough, said disc being slidable around the cylinder to permit the cylinder to rotate relative thereto; a compression coil spring 398 received around the rod 384 in interposition between the upper surface of the cap 372 and the under surface of the disc 396 to normally force the disc, together with the cylinder 392, upwardly; a dashpot type dampener 400 having the piston rod thereof fixedly secured to and extending upwardly from the disc 396 and the cylinder thereof mounted on the bearing member 174; a pair of centrifugal sealing jaws 402 journaled to the cylinder 392 by transverse pivot pins 404 for movement between a position sealingly engaged'with the drill string 146 (see the solid line representation in FIG. 14) and a position disengaged from the drill string (see the phantom line representation in FIG. 14); a semicircular gasket 406 received within each of the sealing jaws 402 for sealing engagement with the drill string 146; a snap ring 408 loosely confined within an annular groove 410 formed in the interior of the cylinder 392 for normal projection partially into the interior of the cylinder; and, a key pin 412 fixed to the cylinder 392 and extending to the interior thereof for slidable engagement with the key slot 280 formed in the couplings 148. i

The upper end of the cylinder 392 and the lower end of the torque tube 170 are formed with mating coupling surfaces 414 and 416, respectively. When the cylinder 392 is in the upper position, as illustrated by the solid line representation in FIG. 14, these surfaces assume mating engagement and rotational movement of the torque tube 170 is transmitted to the cylinder 392. This movement functions to centrifugally swing the jaws 402 into sealed engagement with the outer periphery of the drill string 146. Torsion springs 418 resiliently urge the jaws 402 to a disengaged position when the cylinder 392 is in at rest nonrotating condition.

The cylinder 392 is interiorly dimensioned to slidably receive the couplings 148 to permit their rectilinear movement therethrough during drilling. Each coupling is formed with an annular groove 420 which is proportioned and positioned for releasable engagement by the snap ring 408. The manner in which the groove on one of the couplings 148 cooperates with the snap ring 408 during operation is sequentially illustrated in FIG. 16. In sequence A of this figure, the coupling, 148 is shown in the process of moving through the cylinder 392 prior to engagement of the groove 420 by the snap ring 408 and with the key pin 412 slidably engaged in one of the keyslots 280 in the coupling. As thus conditioned, the coupling 148 does not impart rectilinear movement to the cylinder 392 and the coupling surfaces on the cylinder and the torque tube 170 remain in engagement to transmit rotation of the tube to the cylinder. The latter condition, in turn, functions to maintain the jaws 402 in sealed engagement with the outer periphery of the drill string 146. In sequence B of FIG.

16, the coupling 148 is shown descended to a position wherein the snap ring 408 first engages the groove 420. Upon this occurrence, ,the ring functions to lock the cylinder 392 to the coupling for rectilinear movement therewith in a condition wherein the key pin 412 is retained within the keyslot 280. As thus conditioned, the cylinder 392 is depressed by the coupling 148 so as to move the coupling surfaces 414 and 416 out of engagement. At the same time, however, rotary movement of the cylinder 392 is continued through interengagement of the key pin 412 and the keyslot 280. As a result, the

sealing jaws 402 remain in sealed engagement with the outer periphery of the drill string 146. In sequence C of FIG. 16 the coupling 148 and cylinder 392 are shown in the condition which occurs immediately after the cylinder 392 is depressed to a position wherein the disc 396 abuts against the stop post 382. :Upon this occurrence, the ring 412 snaps out of the groove 420 and the key pin 412 disengages from the keyslot 280. Thus, the cylinder 392 is released from its rotary connection with both the coupling 148 and the torque tube 170. As a result, the cylinder no longer rotates and the jaws 402 swing to an open nonsealing position (see the phantom line representation at the bottom of FIG. 14). This permits the jaws to slide upwardly around the coupling 148 immediately thereabove under the influence of the coil spring398 post 382 and spring 390 are representative of one of several like members disposedaround cylinder 392.

Return'of the cylinder 392 to the upper position illustrated in the solid line representation of FIG. 14 once again engages the coupling surfaces 414 and 416 and, as a result, the cylinder 392 is rotatably driven by the torque tube 170. This, in turn, functions to reengage the jaws 402 with the drill string. As thus conditioned, the shuttle mechanism is once again readied for operation through the FlG. 16 sequence as the drill string passes therethrough during drilling.

It is again emphasized that the primary purpose of the shuttle mechanism is to seal the diverter assembly from the escape of drilling, fluid around the drill string 146 while, at the same time, permit the enlarged couplings to pass through the assembly. This sealing function is necessary in order to assure that the discharge of drilling fluid from the annulus will pass into the branch conduit 358, rather than escape into the body of water within which the assembly is positioned.

The Alternative Connection Between The Drilling Fluid Supply Conduit And Drill String Referring now'to FIG. 17, therein is illustrated a joint 422 suitable for interposition between the drilling fluid conduit 46 and the drill string 146 in place of the fitting 50. With employment of the joint 422, the support station 52 may be omitted in its entirety, as the jointris capable of transmitting tension and, thus, transmitting the load of the drill string 146 to the drilling fluid conduit46. Because of the absence of the support station 52 in a system employing the joint 422, it should be understood that. such a system would be designed primarily for use in relatively shallow water where the length and weight of the drill string was relatively limited.

In FIG. 17, the drilling fluid conduit and drill string are designated by the numerals 46a and 1460, respectively. These elements correspond in all material respects to the conduit 46 and string 146, respectively, with the exception that they are flanged at their opposed end portions. The flanges on the end of the conduit 46a is designated by the numeral 424 and is shown as having an Oring 426 contained in an annular groove formed therein. The flange on the string 146a is designated 420 and is formed with a smooth bearing surface mating with the end surface on the flange 424 for rotation relative thereto.

The O-ring 426 sealingly engages the end surface of the flange 428 to prevent the escape of fluid from between the flanges. The flanges are held together by an annular cap 430 having a collar abutting against the lower surface of the flange 428 and externally threaded ring 432 threadably received within the cap above the flange 424 for sliding engagement therewith. Wrench protrusions 434 are fixed to and extend upwardly from the ring 432 to facilitate the screwing thereof into and out of engagement with the cap 430. Once the'cap and ring are assembled as shown in FIG. 17, a pin 436 is keyed therebetween to prevent their further relative rotation.

As noted in the foregoing discussion, a system employing the joint 422 would difier from that illustrated in FIG. 1 primarily in that the joint would be used in place of the fitting 50 and the support station 52 would be omitted. With latter omission, the guy lines would also require slightmodification. This modification would only amount to omitting the lines 100, 102 and l04and extending the lines 1000, 102a and 104a directly to the alignment mechanism 296a. With this overall arrangement, the control station 34 would function to suspend the composite weight of the drilling fluid conduit and the drilling string. The rotary bearing provided by the joint 422 would permit the drill string to rotate relative to the drilling fluid conduit.

The Drilling Station Guide At this point, it is noted that the base portion 154 of the drilling station is provided with a guide 438 of generally inverted frustoconical configuration to facilitate alignment of the superstructure portion 156 with the base portion. The guide can best be seen from FIGS. 1 and 2 and is made up ofa frameworklike structure comprising a plurality of upwardly divergent members 440' disposed around the base portion; and, an annular ringlike member 442 fixedly secured to the upper ends of the members 440 so as to define an open mouthlike portion. While not illustrated, it is also anticipated that the guide may include structure to effect turning of the superstructure portion relative to the base portion as the two are nested together so as to establish a predetermined rotational relationship therebetween.

In the operation of directing the superstructure portion 156 into alignment with the base portion 154, the guide 438 slidably engages the periphery of the annular flange 162 on the superstructure portion. Through the converging character of the guide, this functions to establish vertical alignment between the superstructure and base portion upon lowering of the superstructure portion. This operation is believed evident from FIG. 2 wherein the superstructure portion is shown disposed above the base portion. Once lowered from the FIG. 2 position to a position within the confines of the guide, the superstructure portion is subjected to the operation of the guide.

The Control Station Leveling Mechanism While not illustrated, it should be under stood that the control station 34 is provided with a control to automatically maintain it in a level condition. This control would operate through the selective charging and discharging of gas from the respective pontoons 40. Any suitable valving and supply structure could be provided for this purpose. The sensing mechanism to control operation of the charging and discharging could correspond to that of the aforedescribed levelling control 248. In this case, however, the levelling control would function to control the operation of the charging and discharging valves for the pontoons 40, rather than the operation of extensible legs.

Installation And Removal Of The System in installation, the submerged components of the system are successively lowered from the service station 20, using the guy lines as suspension means. Most generally, the base and superstructure portions of the drilling station 150 are lowered in assembled condition. The guy lines are progressively lengthened in the operation to provide the desired length of drill string 146 and drilling fluid conduit 46. Where the body of water being worked is sufiiciently deep, the drill string initially lowered is of a length sufficient to effect drilling to the ultimate depth desired. This is advantageous because it permits progressive drilling with simply the addition of drilling fluid conduit lengths and without the necessity of increasing the length of the drill string.

During installation of the system, the drilling fluid return conduit 362 is also progressively lowered simultaneously with the lowering of the drilling station 150. As noted in the foregoing discussion, this conduit is preferably suspended through means of a support system of the type disclosed in may Pat. No. 3,359,741. Accordingly, this system is also progressively lowered simultaneously with the lowering of the drilling system. While not illustrated, it should be understood that the support system for the return conduit 362, or other similar systems, may be employed to run various service lines to the drilling and support stations from the service station 20.

Removal of the drilling system is effected progressively through a sequence substantially the reverse of that used for installation. ln removal, the guy lines are also employed to suspend the various components of the system as they are lifted to the service station 20. It is noted that partial removal may be effected while leaving the base portion 154 of the drilling station 150 on the floor of the body of water being worked. Such partial removal would most commonly be carried out in servicing operations where it is desired to reinstall the system after completion of the servicing operation. Any suitable guide system might be employed to direct the removed components back to the base portion of the drilling station after the servicing operation has been completed.

Drilling Operation In operation, once the drilling system is installed as shown in FIG. 1, drilling is effected by turning the drill string 146 through means of the torque tube 170. This effects turning of the full length of the drill string and penetration of the bit 284 into the floor of the body of water being worked. The fitting 50 permits the drill string to turn relative to the drilling fluid conduit 46 and, accordingly, the conduit does not rotate with the string. The support station 52 is maintained against rotation with the string through the operation of the alignment mechanism 296.

As the bit 284 penetrates the floor of the body of water being worked, the weight of the suspended drill string and drilling fluid conduit assembly functions to pull the support and control stations down, thus maintaining the bit in drilling engagement. During this operation, the drill string translates through the torque tube 170. This operation is provided by maintaining the buoyancy of the support and control stations at a degree insufficient to support the composite weight of the drilling fluid conduit 46, drill string 146 and bit 284. Ideally, the control station 34 is maintained at a buoyancy sufficient to fully support the weight of the conduit 46, but insufficient to lift the support station 52 through the guy lines 100, 102 and 104. Thus, the conduit 46 is fully suspended by the control station, while the guy lines 100, 102 and 104 are maintained under tension. The buoyancy of the support station 52 is preferably maintained at a degree sufficient to support the entire length of the drill string 146, but insufficient to lift the drill bit 284. With this arrangement, the drill string is maintained under tension through its entire length. To facilitate this condition, it is generally necessary to deliberately weight the bit. The pressure applied to the bit may be controlled by controlling the buoyancy of the station 52.

During drilling, the entire composite length of the drill string 146 and conduit 46, together with the stations 34 and 52 secured thereto, moves toward the station 150. The rate at which the drill string is penetrating the floor of the body of water being worked may be determined by monitoring the length of one of the guy lines a, 102a or 104a. This information may, in turn, be employed to determine the pressure to be applied to the drill bit 284 through control of the buoyancy of the support station 52. As the drill string penetrates into the floor of the body of water being worked, the length of the conduit 46 is periodically lengthened, as described in the foregoing discussion. This, in turn, is accompanied by a raising of the station 34 and a lengthening of the guy lines 100, 102 and 104.

The Drilling Method The method of drilling provided by the invention may be defined as comprising the following steps:

I. submerging the drilling station within the body of water being worked to a position supported, at least in part, on the floor of the body;

2. extending the drill string 146 into engagement with the floor of the body;

3. suspending the drill string in a generally upright condition from the buoyant support station 52 while maintaining said station above the drilling station;

4. imparting drilling torque to the drill string from the drilling station to effect penetration of the bit 284 into the floor of the body of water; and, i

5. providing for lowering of the support station as drilling takes place to maintain the drill string in engagement with the floor of the'bo'dy of water during drilling. During the drilling operation, drilling fluid (i.e. mud") is continuously supplied to the bit from the drill string and the conduit 46 connected thereto. This fluid circulates through the bore being drilled and is returned to the service station 20 through the branch 'conduit 358 and the return conduit 362 connected thereto.

The Drill String Positioning Method The invention may also be defined as a method of positioning a drill string for drilling into the floor of a body of water. This method comprises the steps of:

1. extending a drill string having a length less than the depth of a body of water being worked into a submerged condition therein;

2. suspending the drill string in a generally upright condition within the body of water from a buoyant pontoon; and,

3. submerging the pontoon to lower the string into engagement with the floor of the body. As shown in the FIG. 1 system, the drill string of this method would comprise the string 146 and the pontoon would comprise the buoyant pontoon of the support station 52. ln the drilling operation, this method would also comprise the steps of controlling the buoyant lift imparted to the string to maintain substantially the entire length thereof under tension during drilling and permitting the pontoon to lower to maintain the drill string (i.e. the bit thereon) in engagement with the floor of the body of water during drilling.

Conclusion While the foregoing description has concentrated primarily on two embodiments of the system (i.e. those of FIGS. 1 and i 17) it should be understood that the system method and apparatus of the invention may be varied from that illustrated without departing from the invention. For example, it is anticipated that a plurality of support stations might be used in place of the single station 52. Such a plurality could be provided by securing the stations in series above the drill string through means of a support system of the type disclosed in my prior Pat., 3,359,741. it is also anticipated that the control station 34 might take the form of a single pontoon cooperating with the hull of the service station in the manner suggested by my copending application Ser. No. 533,623, filed Mar. ll, 1966. No attempt will here be made to enumerate all of the possible variations, nor other incidental apparatus embodying similar features, i.e., flexible service lines conveying gas or electricity required by various elements. Such lines could employ areel system like that of 118 and if suitable be clustered with bull gear 134.

lclaim:

l. A submerged vertical array for deep well boring into the floor of a body of water, comprising:

a. a drilling station disposed adjacent to the floor with support means adaptable to contend with environmental conditions and floor characteristics for a stable and erect position therewith;

b. a drill string externally bared to the body of water and retained as an integral assembly of a multiplicity of pipe segments locked together by couplings and terminating with fla drill bit bearing upon the floor below the drill station;

c. torque, elements fixed to said. string at longitudinally spaced locations;

d. a turntableexposed to environmental conditions with an integral torque tube projecting concentric therethrough, mounted on the drilling station for rotation relative thereto about a stable vertical axis;

e. at least one rotary drive means mounted on the drilling station in power transmitting engagement with the table and adaptable to immersion in changing environmental conditions;

f. gripping and translation means for automatic and uninterrupted passage of the torque elements through the accommodating torque tube length extending dimensionally in excess of the span between torque elements and said means transmitting solely torque to the string from the tube through the torque elements, and;

g. a buoyant station maintained at selected spaced relationship with the bit and in support of the string thereby tensioned with the buoyant station. free to move vertically relative the drilling station responsive to control of the drill bit bearing on the floor.

2. An underwater drilling station according to claim 1 wherein the support means comprises a plurality of legs for selective bearing upon the floor, at least one of which legs is movable relative to the others to effect leveling of the drilling station, and further comprising:

a. leg actuation means carried by the drilling station to effect movement of said leg independently of the others; and,

b. sensing means to sense the plumb of the drilling station and control the operation of the actuation means responsive thereto.

3. An underwater drilling station according to claim 2 wherein the support means further comprises buoyancy chamber means integral with the drilling station to lend buoyant support thereto, said means being selectively variable to control the amount of buoyant support provided thereby.

4. An underwater drilling station according to claim I wherein the gripping and translation means comprises first and second key means fixed, respectively, to the tube, and couplings and extending longitudinally thereof, said means being mutually engageable to transmit torque from the tube to the string with automatic and uninterrupted axial movement ofthe string through the tube.

5. An underwater drilling station according to claim 4 wherein:

a. the first key means is continuous over an extended length of the tube; and,

b. the second key means is interrupted by lengths less than the continuous length of the first key means.

6. An underwater drilling station according to 1 wherein:

a. the drill string is tubular and open to the bit to provide for the supply of drilling fluid thereto; and,

b. the bit has a drilling diameter greater than the diameter of i the string whereby a hole drilled thereby provides an open annulus around the string: and further comprising;

1. tubular diverter means subjected externally to surrounding natural environmental ,conditions and disposed around the string for sealed fluid communication with the open annulus of a hole drilled by said bit to receive fluidfrom said annulus;

2. a discharge conduit disposed remote to the string and coupled in fluid communication with the diverter means to provide for the discharge of .fluid therefrom; and,

3. seal means interposed between the-,drill string and diverter means above the coupling of the discharge conduit to the diverter means and adjacent the torque tube to substantially prevent fluid flow from the diverter means around the drill string.

7. An underwater drilling station, comprising:

a. a platform; I i

b. support means on the platform adapted to effect the positioning thereof within a body of water in a totally submerged condition disposed adjacent to and supported at least in part on the floor of the body;

c. a turntable mounted on a platform for rotation relative thereto about a generally upright axis;

d. a drill string extending through the turntable and tcrminating in a bit disposed therebeneath for drilling engagement with the floor of a body of water within which the platform is positioned; I e. mutually engageable gripping and translation means on the table and string to impart turning torque from the table to the string and provide for axial translation of the string into the floor of a body of water within which the platform is positioned; and, f. rotary drive means mounted on the platform for submergence therewith, said means being coupled to the turntable to impart turning torque thereto; and wherein:

l. the platfonn is comprised of selectively separable base and tower portions;

2. the turntable is mounted on the tower portion for removal therewith upon separation of the base and tower portions; and,

3. the support means are mounted on the base portion.

8. An underwater drilling station according to claim 7 further comprising guide means mounted, respectively, on the base and tower portions, said means being mutually engageable to direct the tower portion into alignment with the base portion upon lowering of the tower portion onto the base portion.

9. A method of drilling into the floor of a body of water, said method comprising:

a. submerging a drilling station within the body to an adjusted position with support in part by the floor thereof for a stable and erect posture therewith;

b. connecting a weighted drill bit to a multiplicity of pipe segments locked together by couplings and retaining the assembly as an integral string exposed to a natural environment for drilling engagement with the floor;

c. suspending the string in a generally upright condition from a buoyant support station confined within the body of water and adjusted above the drilling station to support at least part of the weight thereof;

d. imparting drilling torque automatically to successively engaged couplings with continuous translation of the string through the drilling station to effect uninterrupted drilling of said floor;

e. lowering the support station commensurate with drilling penetration in contention with consequential environmental changes as drilling takes place to maintain the drill bit bearing with the floor to selected amounts during drilling;

. supplying drilling fluid to the string from a pump connected thereto above the control station; and,

g. controlling support provided by the support station to maintain the string under tension.

10. A method of utilizing a drill string attached bit for drilling into the floor of a body of water, said method comprismg:

a. extending a drill string having a length less than the depth of the body of water into submerged and exposed environmental condition therein as an integrated assembly retained for the duration of drilling with attached bit;

b. suspending the drill string in a generally upright condition from a buoyant pontoon having variable support capacity monitored in contention with imposed load an environmental changes; and,

c. submerging the pontoon unhindered to lower the bit in retained space relationship with the pontoon during drilling.

I]. A method according to claim 10 further comprising controlling the buoyant lift imparted to the string by the pontoon to maintain substantially the entire length of the string under tension during drilling.

12. A method according to claim 11, further comprising continuously submerging the pontoon for sustaining continu ous penetration and selected bearing of the bit with the floor during drilling.

13. A system for drilling into the floor of a body of water, said system comprising: i

a. a drilling station positioned on the floor of the body having a rotary table exposed to environmental conditions;

b. a drill string disposed within the body of water in a generally upright condition and exposed to environmental conditions, said string extending through the station and having a bit at the lower end thereof in drilling engagement with the floor;

c. a buoyant support station disposed within the body of water and secured to the string above the remote drilling station to effect suspension of the the string, and said support station being vertically moveable relative to the drilling station commensurate with bit penetration of the floor; and,

d. torque imparting means exposed to environmental conditions to provide automatic accommodation for passage of the integrated string therethrough to impart drilling torque to the string V 14. A system according to claim 13 wherein:

a. the drilling station is supported on the floor of the body I against rotational movement relative thereto; and,

b. the torque imparting means comprises;

l. at least one torque imparting prime mover adaptable to environmental changes mounted on the drilling station in engagement with the table: and,

2. mutually engaged torque transmitting means disposed,

respectively, on the drilling station and string to transmit uninterrupted drilling torque from the prime mover to the string to provide continuous penetration of the bit into the floor.

15. A system according to claim 14 further comprising pontoon means on the drilling station to buoyantly support at least part of the weight thereof, said means being selectively variable to vary the amount of buoyant support provided thereby and automatically compensating in contention with environmental changes.

16. A system according to claim 13 wherein said buoyant support station comprises a submergible pontoon having bearing means thereon to impart axial support to the string while permitting the string to rotate relative to the pontoon.

17. A system according to claim 13 further comprising:

' a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station;

b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; and, 1

c. monitoring means to the propulsion means to control operation of the propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station 18. A system according to claim 11 further comprising:

a. a plurality of guy lines secured between the drilling station and the support station at spaced locations around the drill string;

b. tension control and takeup means to maintain a predetermined tension on the guy lines and take up the length thereof as the support station descends in accordance with movement of the drill string during drilling.

19. A system for drilling into the floor of a body of water,

said system comprising:

a. a drilling station positioned on the floor of the body;

b. a drill string disposed within the body of water in a generally upright condition, said string extending through the station and having a bit at the lower end thereof in drilling engagement with the floor of the body;

c. a buoyant support station disposed within the body of water and secured to the string above the drilling station to effect suspension of the string, said station being lowerable to provide for movement of the string axially into the floor of the body during drilling and comprising a submergible pontoon having bearing means thereon to impart axial support to the string while permitting the string to rotate relative to the pontoon;

d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string;

e. rotation monitoring means to sense rotational movement of the support station relative to the drilling station;

. rotational propulsion means secured to the support station and propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station; and,

g. control means coupling the rotation monitoring means to the rotational propulsion means to control operation of the propulsion means responsive thereto so as to i 20. A system according to claim 19 further comprising:

a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station;

b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guidedtraversal of the supportstation within the body of water;

c. alignment control means coupling the alignment monitoring means to the propulsion means to control operation of the propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station.

21. A system for drilling into the floor of a body of water,

said system comprising:

a. a drilling station having a rotary table exposed to environmental conditions and erectly positioned on the floor in at least partial load imparting relationship thereto;

b. a bared drill string immersed erectly in the water preassembled to an integrated length less than the depth of water and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit at the lower terminal;

c. a buoyant support station submerged within the body of water and secured to the string above the remotedrilling station to effect suspension of the string, said support station being vertically moveable relative the drilling station commensurate with bit penetration of the floor;

. torque imparting means exposed to natural environmental conditions to provide automatic accommodation for passage of the integrated string therethrough to impart drilling torque to the string below the drilling station;

. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string, saidconduit extending upwardly axially beyond the string to close proximity to the surface of the body of water; and, f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling.

22. A system according to claim 21 wherein:

I a. the drilling station is supported on the floor of the against rotational movement relative thereto; and,

b. the torque imparting means comprises:

1. at least one torque imparting prime mover adaptable to environmental changes mounted on the drilling station in engagement with the table; and,

2. mutually engaged torque transmitting means disposed,

respectively, on the drilling station and string to transmit uninterrupted drilling torque from the prime mover to the string to automatically provide continuous penetration of the bit into the floor.v

23. A system according to claim 21 wherein:

a. the bit has a drilling diameter greater than the diameter of the string whereby a hole drilled thereby provides an open annulus around the string; and further comprising;

1. tubular diverter means subjected externally to sur' rounding natural environmental conditions and disposedaround the string for sealed fluid communication with the open annulus of a hole drilled by said bit to receive fluid from said annulus;

2. a tubular discharge branch disposed remote to the string and coupled in fluid communication with the diverter means to provide for the discharge of fluid therefrom;

3. seal means interposed between the drill string and diverter means above the coupling of the discharge branch to the diverter means and adjacent the torque means to substantially prevent fluid flow from. the diverter means around the drill string; and,

body

4. a secondary drilling fluid conduit secured in fluid communication with the discharge branch and extending upwardly therefrom to the surface of the body of water in spaced relationship to the drill string.

24. A system according to claim 21 drilling fluid conduit is secured to the drill string for axial and rotational movement relative thereto to provide for limited relative axial movement between the conduit and string and permit the string to rotate relative to the conduit.

25. A system according to claim 21 further comprising:

a. a buoyant service station disposed on the surface of the body of water; and,

b. guide means securing the control station to the service station to permit the control station to be submerged relative to the service station and maintain said stations in substantial vertical alignment. 26. A system according to claim 25, further comprising: a. tension transmitting means secured between the support and control stations to maintain a predetermined distance thereb etween as the support station lowers during drilling and, thus, pull the control station down simultaneously with the lowering of the support station; and,

b length control means to selectively vary the length of the tension transmitting means and, thus, the predetennined distance between the support and control stations.

27. A system for drilling into the floor of a body of water,

said system comprising:

a. a drilling station positioned on the: floor of the body in at I least partial load imparting relationship thereto;

b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being;

- tubular to i provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit;

0. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, and support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling;

d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the :string;

e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to closeproximity to the surface of the body of water;

f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling;

g. rotation monitoring means to sense rotational movement of the support station relative to the drilling station;

h. rotational propulsion means secured to the support station said propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station; and,

i. rotational control means coupling the rotation monitoring means to the rotational propulsion means to control operation of the propulsion means responsive thereto so as to substantially maintain the support station against rotational movement relative to the drilling station.

28. A system according to claim 27 further comprising:

a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station;

b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water;

c. alignment control means coupling the alignment monitoring means to the propulsion means to control operation of wherein the primary 1 said system comprising:

a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto;

b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit;

. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling;

. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string;

. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water;

f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the con duit with the string during drilling;

alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station;

. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; and

. alignment control means coupling the alignment monitoring means to the propulsion means responsive thereto so as to support station in substantial vertical alignment with the drilling station.

30. A system for drilling into the floor of a body of water,

said system comprising: a

a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto;

b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit;

c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling;

d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string;

e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water;

f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling; 4

g. a buoyant service station disposed on the surface of the body of water;

h. guide means securing the control station to the service station to permit the control station to be submerged rela- -24 tive to the service station and maintain said stations in substantial vertical alignment; v

i. tension transmitting means secured between the support and control stations to maintain a predetermined distance therebetween as the support station lowers during" drilling and, thus, pull the control station down simultaneously with the lowering of the support station;

j. length control means to selectively vary the length of the tension transmitting means and, thus, the predetermined distance between the support and control station;

k. conduit handling means on said service station to selectively vary the length of the primary drilling fluid conduit. 31 A system for drilling into the floor of a body of water,

said system comprising:

a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto; 5

b. a drill string of a length less than the depth of the-body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit;

c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling;

d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string;

e. a primary drilling fluid conduit secured in fluid a communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water;

f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling;

.- a buoyant service station disposed on the surface of the body of water;

h. guide means securing the control station to the service station to permit the control station to be submerged relative to the service station and maintain said stations in substantial vertical alignment;

. a first alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station;

j. first alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water;

k. first alignment control means coupling the first alignment monitoring means to the first alignment propulsion means to control operation of said propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station;

alignment of the control station relative to the support station;

n. second alignment propulsion means secured to the sersecond alignment monitoring means to sense vertical mis- 32. A system according to claim 31 wherein the drill string is secured to the buoyant support station for rotation relative thereto and further comprising:

a. first rotation monitoring means to sense rotational movement of the support station relative to the drilling station;

b. first rotational propulsion means securedto the support station, said propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station;

. first rotation control means coupling the first rotation monitoring means to the first rotational propulsion means to control operation of said propulsion means responsive thereto so as to substantially maintain the support station against rotational movement relative to the drilling station;

cl. second rotation monitoring means to sense rotational movement of the control station relative to station;

the support second rotational propulsion means secured to the service station, said propulsion means being selectively operable to effect rotational movement of the service station and resultant rotational movement of the control station relative to the support station, and,

f. second rotational control means coupling the second rotation monitoring means to the second rotational propulsion means to control operation of said propulsion means responsive thereto so as to substantially maintain the control station against rotational movement relative to the support station.

33. A system for drilling into the floor of a body of water, said system comprising:

a. a drilling station erectly positioned on the floor in at least partial load imparting relationship thereto;

b. a bared drill string immersed erectly in the water as a preassembled retained integral length extending through the drilling station and being tubular and open to provide for the supply of drilling fluid to the bit at the lower end thereof;

. a primary drilling fluid conduit secured in fluid communid. a buoyant control station disposed within the body of water above the drilling station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for controlled bearing of the bit on the floor during drilling; and

e. torque imparting means exposed to natural environmental conditions accommodating automatic and uninterrupted passage of the string comprising a multiplicity of pipe segments locked together by couplings spaced to provide successive engagement with the means incorporated with the drilling station to impart continuous torque to the string.

34. An apparatus for imparting torque from a rotating turntable to a drill string while permitting the drill string to translate axially through the table, said apparatus comprising:

and coupling and extending longitudinally thereof, said means being mutually engageable to transm|t torque continuously from the tube to the string while permitting uninterrupted axial movement of the string through the tube.

35. An underwater drilling station according to claim 34 wherein:

a. the first key means is continuous over an extended length of the tube; and,

b. the second key means is interrupted by lengths less than the continuous length of the first key means.

36. A method of utilizing a drill string supported bit for drilling into the floor of a body of water, said method comprising:

a. suspending the drill string bared to the natural elements from a totally immersed buoyantly controlled support station;

b. maintaining selected spaced relationship of the drill bit below the support station;

. c. effecting the immersion of the station by selectively providing a deficiency to the support of the drill string;

d. opposing said deficiency by engagement of the drill bit with the floor while sustaining tension in the suspended string;

e. controlling the force imparted by the bit to the floor by controlling said deficiency; and,

f. rotating the bit to effect penetration of the floor by a torque means accommodating the string retained as an integral length for uninterrupted passage therethrough.

37. A method according to claim 37, further comprising:

a. extending the drill string to effect maximum uninterrupted penetration thereof into the floor by preassembling the string length commensurate with the maximum head of water below the immersed support station when in vicinity of the water surface; and,

b. prolonging penetration of the floor by retaining a deficiency of the support provided during continuous descent to the vicinity of the floor ultimately reached by the support station coincident with the uninterrupted penetration.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,593,808 Dated July 20, 1971 Arthur J. Nelson Inventor-(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 20, line 1, "14" should read 13 line 40, before "monitoring" insert alignment control means coupling the alignment line 44, "ll" should read 13 Column 21, line 3, after "so as to" insert substantially maintain the support station against rotational movement relative the drilling station. line 37, after "string" insert to provide for the supply of drilling fluid thereto Column 23, line 40, before "responsive" insert to control operation of the propulsion means Column 26, line 46, "37" should read 36 Signed and sealed this 27th day of June 1972.

(SEAL) Attest:

EDWARD M. FLETCIIER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 1 FORM PO-1050 (10-69) USCOMM-DC 60376 Pu f R US GOVERNMENT PRINTING OFFICE I968 0-3662!!! 

1. A submerged vertical array for deep well boring into the floor of a body of water, comprising: a. a drilling station disposed adjacent to the floor with support means adaptable to contend with environmental conditions and floor characteristics for a stable and erect position therewith; b. a drill string externally bared to the body of water and retained as an integral assembly of a multiplicity of pipe segments locked together by couplings and terminating with a drill bit bearing upon the floor below the drill station; c. torque elements fixed to said string at longitudinally spaced locations; d. a turntable exposed to environmental Conditions with an integral torque tube projecting concentric therethrough, mounted on the drilling station for rotation relative thereto about a stable vertical axis; e. at least one rotary drive means mounted on the drilling station in power transmitting engagement with the table and adaptable to immersion in changing environmental conditions; f. gripping and translation means for automatic and uninterrupted passage of the torque elements through the accommodating torque tube length extending dimensionally in excess of the span between torque elements and said means transmitting solely torque to the string from the tube through the torque elements, and; g. a buoyant station maintained at selected spaced relationship with the bit and in support of the string thereby tensioned with the buoyant station free to move vertically relative the drilling station responsive to control of the drill bit bearing on the floor.
 2. An underwater drilling station according to claim 1 wherein the support means comprises a plurality of legs for selective bearing upon the floor, at least one of which legs is movable relative to the others to effect leveling of the drilling station, and further comprising: a. leg actuation means carried by the drilling station to effect movement of said leg independently of the others; and, b. sensing means to sense the plumb of the drilling station and control the operation of the actuation means responsive thereto.
 2. a tubular discharge branch disposed remote to the string and coupled in fluid communication with the diverter means to provide for the discharge of fluid therefrom;
 2. mutually engaged torque transmitting means disposed, respectively, on the drilling station and string to transmit uninterrupted drilling torque from the prime mover to the string to automatically provide continuous penetration of the bit into the floor.
 2. mutually engaged torque transmitting means disposed, respectively, on the drilling station and string to transmit uninterrupted drilling torque from the prime mover to the string to provide continuous penetration of the bit into the floor.
 2. the turntable is mounted on the tower portion for removal therewith upon separation of the base and tower portions; and,
 2. a discharge conduit disposed remote to the string and coupled in fluid communication with the diverter means to provide for the discharge of fluid therefrom; and,
 3. the support means are mounted on the base portion.
 3. seal means interposed between the drill string and diverter means above the coupling of the discharge conduit to the diverter means and adjacent the torque tube to substantially prevent fluid flow from the diverter means around the drill string.
 3. seal means interposed between the drill string and diverter means above the coupling of the discharge branch to the diverter means and adjacent the torque means to substantially prevent fluid flow from the diverter means around the drill string; and,
 3. An underwater drilling station according to claim 2 wherein the support means further comprises buoyancy chamber means integral with the drilling station to lend buoyant support thereto, said means being selectively variable to control the amount of buoyant support provided thereby.
 4. a secondary drilling fluid conduit secured in fluid communication with the discharge branch and extending upwardly therefrom to the surface of the body of water in spaced relationship to the drill string.
 4. An underwater drilling station according to claim 1 wherein the gripping and translation means comprises first and second key means fixed, respectively, to the tube and couplings and extending longitudinally thereof, said means being mutually engageable to transmit torque from the tube to the string with automatic and uninterrupted axial movement of the string through the tube.
 5. An underwater drilling station according to claim 4 wherein: a. the first key means is continuous over an extended length of the tube; and, b. the second key means is interrupted by lengths less than the continuous length of the first key means.
 6. An underwater drilling station according to 1 wherein: a. the drill string is tubular and open to the bit to provide for the supply of drilling fluid thereto; and, b. the bit has a drilling diameter greater than the diameter of the string whereby a hole drilled thereby provides an open annulus around the string: and further comprising;
 7. An underwater drilling station, comprising: a. a platform; b. support means on the platform adapted to effect the positioning thereof within a body of water in a totally submerged condition disposed adjacent to and supported at least in part on the floor of the body; c. a turntable mounted on a platform for rotation relative thereto about a generally upright axis; d. a drill string extending through the turntable and terminating in a bit disposed therebeneath for drilling engagement with the floor of a body of water within which the pLatform is positioned; e. mutually engageable gripping and translation means on the table and string to impart turning torque from the table to the string and provide for axial translation of the string into the floor of a body of water within which the platform is positioned; and, f. rotary drive means mounted on the platform for submergence therewith, said means being coupled to the turntable to impart turning torque thereto; and wherein:
 8. An underwater drilling station according to claim 7 further comprising guide means mounted, respectively, on the base and tower portions, said means being mutually engageable to direct the tower portion into alignment with the base portion upon lowering of the tower portion onto the base portion.
 9. A method of drilling into the floor of a body of water, said method comprising: a. submerging a drilling station within the body to an adjusted position with support in part by the floor thereof for a stable and erect posture therewith; b. connecting a weighted drill bit to a multiplicity of pipe segments locked together by couplings and retaining the assembly as an integral string exposed to a natural environment for drilling engagement with the floor; c. suspending the string in a generally upright condition from a buoyant support station confined within the body of water and adjusted above the drilling station to support at least part of the weight thereof; d. imparting drilling torque automatically to successively engaged couplings with continuous translation of the string through the drilling station to effect uninterrupted drilling of said floor; e. lowering the support station commensurate with drilling penetration in contention with consequential environmental changes as drilling takes place to maintain the drill bit bearing with the floor to selected amounts during drilling; f. supplying drilling fluid to the string from a pump connected thereto above the control station; and, g. controlling support provided by the support station to maintain the string under tension.
 10. A method of utilizing a drill string attached bit for drilling into the floor of a body of water, said method comprising: a. extending a drill string having a length less than the depth of the body of water into submerged and exposed environmental condition therein as an integrated assembly retained for the duration of drilling with attached bit; b. suspending the drill string in a generally upright condition from a buoyant pontoon having variable support capacity monitored in contention with imposed load an environmental changes; and, c. submerging the pontoon unhindered to lower the bit in retained space relationship with the pontoon during drilling.
 11. A method according to claim 10 further comprising controlling the buoyant lift imparted to the string by the pontoon to maintain substantially the entire length of the string under tension during drilling.
 12. A method according to claim 11, further comprising continuously submerging the pontoon for sustaining continuous penetration and selected bearing of the bit with the floor during drilling.
 13. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station positioned on the floor of the body having a rotary table exposed to environmental conditions; b. a drill string disposed within the body of water in a generally upright condition and exposed to environmental conditions, said string extending through the station and having a bit at the lower end thereof in drilling engagement with the floor; c. a buoyant support station disposed within the body of water and secured to the string abovE the remote drilling station to effect suspension of the the string, and said support station being vertically moveable relative to the drilling station commensurate with bit penetration of the floor; and, d. torque imparting means exposed to environmental conditions to provide automatic accommodation for passage of the integrated string therethrough to impart drilling torque to the string.
 14. A system according to claim 13 wherein: a. the drilling station is supported on the floor of the body against rotational movement relative thereto; and, b. the torque imparting means comprises;
 15. A system according to claim 14 further comprising pontoon means on the drilling station to buoyantly support at least part of the weight thereof, said means being selectively variable to vary the amount of buoyant support provided thereby and automatically compensating in contention with environmental changes.
 16. A system according to claim 13 wherein said buoyant support station comprises a submergible pontoon having bearing means thereon to impart axial support to the string while permitting the string to rotate relative to the pontoon.
 17. A system according to claim 13 further comprising: a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station; b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; and, c. monitoring means to the propulsion means to control operation of the propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station
 18. A system according to claim 11 further comprising: a. a plurality of guy lines secured between the drilling station and the support station at spaced locations around the drill string; b. tension control and takeup means to maintain a predetermined tension on the guy lines and take up the length thereof as the support station descends in accordance with movement of the drill string during drilling.
 19. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station positioned on the floor of the body; b. a drill string disposed within the body of water in a generally upright condition, said string extending through the station and having a bit at the lower end thereof in drilling engagement with the floor of the body; c. a buoyant support station disposed within the body of water and secured to the string above the drilling station to effect suspension of the string, said station being lowerable to provide for movement of the string axially into the floor of the body during drilling and comprising a submergible pontoon having bearing means thereon to impart axial support to the string while permitting the string to rotate relative to the pontoon; d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string; e. rotation monitoring means to sense rotational movement of the support station relative to the drilling station; f. rotational propulsion means secured to the support station and propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station; and, g. control means coupling the rotation monitoring means to the rotational propulsion means to control operation of the propulsion means reSponsive thereto so as to
 20. A system according to claim 19 further comprising: a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station; b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; c. alignment control means coupling the alignment monitoring means to the propulsion means to control operation of the propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station.
 21. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station having a rotary table exposed to environmental conditions and erectly positioned on the floor in at least partial load imparting relationship thereto; b. a bared drill string immersed erectly in the water preassembled to an integrated length less than the depth of water and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit at the lower terminal; c. a buoyant support station submerged within the body of water and secured to the string above the remote drilling station to effect suspension of the string, said support station being vertically moveable relative the drilling station commensurate with bit penetration of the floor; d. torque imparting means exposed to natural environmental conditions to provide automatic accommodation for passage of the integrated string therethrough to impart drilling torque to the string below the drilling station; e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string, said conduit extending upwardly axially beyond the string to close proximity to the surface of the body of water; and, f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling.
 22. A system according to claim 21 wherein: a. the drilling station is supported on the floor of the body against rotational movement relative thereto; and, b. the torque imparting means comprises:
 23. A system according to claim 21 wherein: a. the bit has a drilling diameter greater than the diameter of the string whereby a hole drilled thereby provides an open annulus around the string; and further comprising;
 24. A system according to claim 21 wherein The primary drilling fluid conduit is secured to the drill string for axial and rotational movement relative thereto to provide for limited relative axial movement between the conduit and string and permit the string to rotate relative to the conduit.
 25. A system according to claim 21 further comprising: a. a buoyant service station disposed on the surface of the body of water; and, b. guide means securing the control station to the service station to permit the control station to be submerged relative to the service station and maintain said stations in substantial vertical alignment.
 26. A system according to claim 25, further comprising: a. tension transmitting means secured between the support and control stations to maintain a predetermined distance therebetween as the support station lowers during drilling and, thus, pull the control station down simultaneously with the lowering of the support station; and, b. length control means to selectively vary the length of the tension transmitting means and, thus, the predetermined distance between the support and control stations.
 27. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto; b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit; c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, and support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling; d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string; e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water; f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling; g. rotation monitoring means to sense rotational movement of the support station relative to the drilling station; h. rotational propulsion means secured to the support station said propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station; and, i. rotational control means coupling the rotation monitoring means to the rotational propulsion means to control operation of the propulsion means responsive thereto so as to substantially maintain the support station against rotational movement relative to the drilling station.
 28. A system according to claim 27 further comprising: a. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station; b. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; c. alignment control means coupling the alignment monitoring means to the propulsion means to control operation of the propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station.
 29. A system for drilling into the floor of a body of water, said system comprising: a. a drilling sTation positioned on the floor of the body in at least partial load imparting relationship thereto; b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit; c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling; d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string; e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water; f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling; g. alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station; h. alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; and i. alignment control means coupling the alignment monitoring means to the propulsion means responsive thereto so as to support station in substantial vertical alignment with the drilling station.
 30. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto; b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit; c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling; d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string; e. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water; f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling; g. a buoyant service station disposed on the surface of the body of water; h. guide means securing the control station to the service station to permit the control station to be submerged relative to the service station and maintain said stations in substantial vertical alignment; i. tension transmitting means secured between the support and control stations to maintain a predetermined distance therebetween as the support station lowers during drilling and, thus, pull the control station down simultAneously with the lowering of the support station; j. length control means to selectively vary the length of the tension transmitting means and, thus, the predetermined distance between the support and control station; k. conduit handling means on said service station to selectively vary the length of the primary drilling fluid conduit. 31 A system for drilling into the floor of a body of water, said system comprising: a. a drilling station positioned on the floor of the body in at least partial load imparting relationship thereto; b. a drill string of a length less than the depth of the body of water disposed within the body in a generally upright condition, said string having a bit at the lower end thereof in drilling engagement with the floor of the body and being tubular to provide for the passage of drilling fluid therethrough from an upper portion thereof to the bit; c. a buoyant support station submerged within the body of water and secured to the string above the drilling station to effect suspension of the string, said support station being lowerable to provide for movement of the string axially into the floor of the body of water during drilling; d. torque imparting means submerged within the body of water and secured to the string beneath the support station to impart drilling torque to the string; e. a primary drilling fluid conduit secured in fluid a communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water; f. a buoyant control station disposed within the body of water above the support station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for downward movement of the conduit with the string during drilling; g. a buoyant service station disposed on the surface of the body of water; h. guide means securing the control station to the service station to permit the control station to be submerged relative to the service station and maintain said stations in substantial vertical alignment; i. a first alignment monitoring means to sense vertical misalignment of the support station relative to the drilling station; j. first alignment propulsion means secured to the support station, said propulsion means being selectively operable to effect the guided traversal of the support station within the body of water; k. first alignment control means coupling the first alignment monitoring means to the first alignment propulsion means to control operation of said propulsion means responsive thereto so as to maintain the support station in substantial vertical alignment with the drilling station;
 32. A system according to claim 31 wherein the drill string is secured to the buoyant support station for rotation relative thereto and further comprising: a. first rotation monitoring means to sense rotational movement of the support station relative to the drilling station; b. first rotational propulsion means secured to the support station, said propulsion means being selectively operable to effect rotational movement of the support station relative to the drilling station; c. first rotation control means coupling the first rOtation monitoring means to the first rotational propulsion means to control operation of said propulsion means responsive thereto so as to substantially maintain the support station against rotational movement relative to the drilling station; d. second rotation monitoring means to sense rotational movement of the control station relative to the support station; e. second rotational propulsion means secured to the service station, said propulsion means being selectively operable to effect rotational movement of the service station and resultant rotational movement of the control station relative to the support station, and, f. second rotational control means coupling the second rotation monitoring means to the second rotational propulsion means to control operation of said propulsion means responsive thereto so as to substantially maintain the control station against rotational movement relative to the support station.
 33. A system for drilling into the floor of a body of water, said system comprising: a. a drilling station erectly positioned on the floor in at least partial load imparting relationship thereto; b. a bared drill string immersed erectly in the water as a preassembled retained integral length extending through the drilling station and being tubular and open to provide for the supply of drilling fluid to the bit at the lower end thereof; c. a primary drilling fluid conduit secured in fluid communication with an upper portion of the drill string to provide for the supply of drilling fluid thereto, said conduit extending upwardly from the string to close proximity to the surface of the body of water and being secured in tension transmitting relationship to the string for rotation relative thereto to provide for the imparting of support to the string and permit the string to rotate relative to the conduit; d. a buoyant control station disposed within the body of water above the drilling station, said control station being secured to the conduit to effect suspension thereof and lowerable to provide for controlled bearing of the bit on the floor during drilling; and e. torque imparting means exposed to natural environmental conditions accommodating automatic and uninterrupted passage of the string comprising a multiplicity of pipe segments locked together by couplings spaced to provide successive engagement with the means incorporated with the drilling station to impart continuous torque to the string.
 34. An apparatus for imparting torque from a rotating turntable to a drill string while permitting the drill string to translate axially through the table, said apparatus comprising: a. a drill string externally bared to surrounding natural elements and supported as a tensioned integral length of a multiplicity of pipe segments locked together by couplings and terminating with a drill bit disposed below the turntable; b. a torque tube integral with the turntable for rotation therewith, said tube being axially open and slidably receiving the drill string therein whereby the string may be extended through and relative to the tube; and, c. first and second key means fixed, respectively, to the tube and coupling and extending longitudinally thereof, said means being mutually engageable to transmit torque continuously from the tube to the string while permitting uninterrupted axial movement of the string through the tube.
 35. An underwater drilling station according to claim 34 wherein: a. the first key means is continuous over an extended length of the tube; and, b. the second key means is interrupted by lengths less than the continuous length of the first key means.
 36. A method of utilizing a drill string supported bit for drilling into the floor of a body of water, said method comprising: a. suspending the drill string bared to the natural elements from a totally immersed buoyantly controlled support station; b. maintaining selected spaced relationship of the drill bit Below the support station; c. effecting the immersion of the station by selectively providing a deficiency to the support of the drill string; d. opposing said deficiency by engagement of the drill bit with the floor while sustaining tension in the suspended string; e. controlling the force imparted by the bit to the floor by controlling said deficiency; and, f. rotating the bit to effect penetration of the floor by a torque means accommodating the string retained as an integral length for uninterrupted passage therethrough.
 37. A method according to claim 37, further comprising: a. extending the drill string to effect maximum uninterrupted penetration thereof into the floor by preassembling the string length commensurate with the maximum head of water below the immersed support station when in vicinity of the water surface; and, b. prolonging penetration of the floor by retaining a deficiency of the support provided during continuous descent to the vicinity of the floor ultimately reached by the support station coincident with the uninterrupted penetration. 